How to upgrade Asterisk & Zaptel on Ubuntu

I am currently running * version 1.4.19.2 on Ubuntu. Being somewhat of a Linux noobie, I would appreciate some help with specific instructions to upgrade * to the current version. Is the following the correct sequence?

$ sudo /etc/init.d/asterisk stop $ sudo make clean $ sudo make menuselect $ sudo make install $ sudo /etc/init.d/asterisk start
Will my existing config. files be maintained, or should I back them up?

Likewise for Zaptel:

$ sudo /etc/init.d/zaptel stop $ sudo rmmod wctdm $ sudo rmmod zaptel $ sudo make clean $ sudo make menuselect $ sudo make $ sudo make install $ sudo /etc/init.d/zaptel start $ sudo modprobe wctdm $ sudo modprobe zaptel

Many thanks in advance,
J.

Always backup, I have upgraded plenty of times and never had a problem, but it takes one slip up. I backup all files after I make changes and before I do an upgrade.